---

yaml
---
r: 58793
b: refs/heads/master
c: 31b54f4
h: refs/heads/master
i:
  58791: 89f55a9
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0008ea39bd03ee1f29e361e6f6e1b8a6289e5234
+refs/heads/master: 31b54f40e12e4d04941762be6615edaf3c6ed811

trunk/arch/i386/boot/cpu.c

@@ -0,0 +1,69 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/cpu.c
+ *
+ * Check for obligatory CPU features and abort if the features are not
+ * present.
+ */
+
+#include "boot.h"
+#include "bitops.h"
+#include <asm/cpufeature.h>
+
+static char *cpu_name(int level)
+{
+	static char buf[6];
+
+	if (level == 64) {
+		return "x86-64";
+	} else {
+		sprintf(buf, "i%d86", level);
+		return buf;
+	}
+}
+
+int validate_cpu(void)
+{
+	u32 *err_flags;
+	int cpu_level, req_level;
+
+	check_cpu(&cpu_level, &req_level, &err_flags);
+
+	if (cpu_level < req_level) {
+		printf("This kernel requires an %s CPU, ",
+		       cpu_name(req_level));
+		printf("but only detected an %s CPU.\n",
+		       cpu_name(cpu_level));
+		return -1;
+	}
+
+	if (err_flags) {
+		int i, j;
+		puts("This kernel requires the following features "
+		     "not present on the CPU:\n");
+
+		for (i = 0; i < NCAPINTS; i++) {
+			u32 e = err_flags[i];
+
+			for (j = 0; j < 32; j++) {
+				if (e & 1)
+					printf("%d:%d ", i, j);
+
+				e >>= 1;
+			}
+		}
+		putchar('\n');
+		return -1;
+	} else {
+		return 0;
+	}
+}

trunk/arch/i386/boot/cpucheck.c

@@ -0,0 +1,267 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/cpucheck.c
+ *
+ * Check for obligatory CPU features and abort if the features are not
+ * present.  This code should be compilable as 16-, 32- or 64-bit
+ * code, so be very careful with types and inline assembly.
+ *
+ * This code should not contain any messages; that requires an
+ * additional wrapper.
+ *
+ * As written, this code is not safe for inclusion into the kernel
+ * proper (after FPU initialization, in particular).
+ */
+
+#ifdef _SETUP
+# include "boot.h"
+# include "bitops.h"
+#endif
+#include <linux/types.h>
+#include <asm/cpufeature.h>
+#include <asm/processor-flags.h>
+#include <asm/required-features.h>
+#include <asm/msr-index.h>
+
+struct cpu_features {
+	int level;		/* Family, or 64 for x86-64 */
+	int model;
+	u32 flags[NCAPINTS];
+};
+
+static struct cpu_features cpu;
+static u32 cpu_vendor[3];
+static u32 err_flags[NCAPINTS];
+
+#ifdef CONFIG_X86_64
+static const int req_level = 64;
+#elif defined(CONFIG_X86_MINIMUM_CPU_FAMILY)
+static const int req_level = CONFIG_X86_MINIMUM_CPU_FAMILY;
+#else
+static const int req_level = 3;
+#endif
+
+static const u32 req_flags[NCAPINTS] =
+{
+	REQUIRED_MASK0,
+	REQUIRED_MASK1,
+	REQUIRED_MASK2,
+	REQUIRED_MASK3,
+	REQUIRED_MASK4,
+	REQUIRED_MASK5,
+	REQUIRED_MASK6,
+	REQUIRED_MASK7,
+};
+
+#define A32(a,b,c,d) (((d) << 24)+((c) << 16)+((b) << 8)+(a))
+
+static int is_amd(void)
+{
+	return cpu_vendor[0] == A32('A','u','t','h') &&
+	       cpu_vendor[1] == A32('e','n','t','i') &&
+	       cpu_vendor[2] == A32('c','A','M','D');
+}
+
+static int is_centaur(void)
+{
+	return cpu_vendor[0] == A32('C','e','n','t') &&
+	       cpu_vendor[1] == A32('a','u','r','H') &&
+	       cpu_vendor[2] == A32('a','u','l','s');
+}
+
+static int is_transmeta(void)
+{
+	return cpu_vendor[0] == A32('G','e','n','u') &&
+	       cpu_vendor[1] == A32('i','n','e','T') &&
+	       cpu_vendor[2] == A32('M','x','8','6');
+}
+
+static int has_fpu(void)
+{
+	u16 fcw = -1, fsw = -1;
+	u32 cr0;
+
+	asm("movl %%cr0,%0" : "=r" (cr0));
+	if (cr0 & (X86_CR0_EM|X86_CR0_TS)) {
+		cr0 &= ~(X86_CR0_EM|X86_CR0_TS);
+		asm volatile("movl %0,%%cr0" : : "r" (cr0));
+	}
+
+	asm("fninit ; fnstsw %0 ; fnstcw %1" : "+m" (fsw), "+m" (fcw));
+
+	return fsw == 0 && (fcw & 0x103f) == 0x003f;
+}
+
+static int has_eflag(u32 mask)
+{
+	u32 f0, f1;
+
+	asm("pushfl ; "
+	    "pushfl ; "
+	    "popl %0 ; "
+	    "movl %0,%1 ; "
+	    "xorl %2,%1 ; "
+	    "pushl %1 ; "
+	    "popfl ; "
+	    "pushfl ; "
+	    "popl %1 ; "
+	    "popfl"
+	    : "=r" (f0), "=r" (f1)
+	    : "g" (mask));
+
+	return !!((f0^f1) & mask);
+}
+
+static void get_flags(void)
+{
+	u32 max_intel_level, max_amd_level;
+	u32 tfms;
+
+	if (has_fpu())
+		set_bit(X86_FEATURE_FPU, cpu.flags);
+
+	if (has_eflag(X86_EFLAGS_ID)) {
+		asm("cpuid"
+		    : "=a" (max_intel_level),
+		      "=b" (cpu_vendor[0]),
+		      "=d" (cpu_vendor[1]),
+		      "=c" (cpu_vendor[2])
+		    : "a" (0));
+
+		if (max_intel_level >= 0x00000001 &&
+		    max_intel_level <= 0x0000ffff) {
+			asm("cpuid"
+			    : "=a" (tfms),
+			      "=c" (cpu.flags[4]),
+			      "=d" (cpu.flags[0])
+			    : "a" (0x00000001)
+			    : "ebx");
+			cpu.level = (tfms >> 8) & 15;
+			cpu.model = (tfms >> 4) & 15;
+			if (cpu.level >= 6)
+				cpu.model += ((tfms >> 16) & 0xf) << 4;
+		}
+
+		asm("cpuid"
+		    : "=a" (max_amd_level)
+		    : "a" (0x80000000)
+		    : "ebx", "ecx", "edx");
+
+		if (max_amd_level >= 0x80000001 &&
+		    max_amd_level <= 0x8000ffff) {
+			u32 eax = 0x80000001;
+			asm("cpuid"
+			    : "+a" (eax),
+			      "=c" (cpu.flags[6]),
+			      "=d" (cpu.flags[1])
+			    : : "ebx");
+		}
+	}
+}
+
+/* Returns a bitmask of which words we have error bits in */
+static int check_flags(void)
+{
+	u32 err;
+	int i;
+
+	err = 0;
+	for (i = 0; i < NCAPINTS; i++) {
+		err_flags[i] = req_flags[i] & ~cpu.flags[i];
+		if (err_flags[i])
+			err |= 1 << i;
+	}
+
+	return err;
+}
+
+/*
+ * Returns -1 on error.
+ *
+ * *cpu_level is set to the current CPU level; *req_level to the required
+ * level.  x86-64 is considered level 64 for this purpose.
+ *
+ * *err_flags_ptr is set to the flags error array if there are flags missing.
+ */
+int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr)
+{
+	int err;
+
+	memset(&cpu.flags, 0, sizeof cpu.flags);
+	cpu.level = 3;
+
+	if (has_eflag(X86_EFLAGS_AC))
+		cpu.level = 4;
+
+	get_flags();
+	err = check_flags();
+
+	if (test_bit(X86_FEATURE_LM, cpu.flags))
+		cpu.level = 64;
+
+	if (err == 0x01 &&
+	    !(err_flags[0] &
+	      ~((1 << X86_FEATURE_XMM)|(1 << X86_FEATURE_XMM2))) &&
+	    is_amd()) {
+		/* If this is an AMD and we're only missing SSE+SSE2, try to
+		   turn them on */
+
+		u32 ecx = MSR_K7_HWCR;
+		u32 eax, edx;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		eax &= ~(1 << 15);
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		get_flags();	/* Make sure it really did something */
+		err = check_flags();
+	} else if (err == 0x01 &&
+		   !(err_flags[0] & ~(1 << X86_FEATURE_CX8)) &&
+		   is_centaur() && cpu.model >= 6) {
+		/* If this is a VIA C3, we might have to enable CX8
+		   explicitly */
+
+		u32 ecx = MSR_VIA_FCR;
+		u32 eax, edx;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		eax |= (1<<1)|(1<<7);
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		set_bit(X86_FEATURE_CX8, cpu.flags);
+		err = check_flags();
+	} else if (err == 0x01 && is_transmeta()) {
+		/* Transmeta might have masked feature bits in word 0 */
+
+		u32 ecx = 0x80860004;
+		u32 eax, edx;
+		u32 level = 1;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		asm("wrmsr" : : "a" (~0), "d" (edx), "c" (ecx));
+		asm("cpuid"
+		    : "+a" (level), "=d" (cpu.flags[0])
+		    : : "ecx", "ebx");
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		err = check_flags();
+	}
+
+	if (err_flags_ptr)
+		*err_flags_ptr = err ? err_flags : NULL;
+	if (cpu_level_ptr)
+		*cpu_level_ptr = cpu.level;
+	if (req_level_ptr)
+		*req_level_ptr = req_level;
+
+	return (cpu.level < req_level || err) ? -1 : 0;
+}